Abstract: A data gathering system adapted to be installed within a checkout counter for determining information about products presented for purchase at the counter including the weight of such products comprises two support flanges within the checkout counter. The support flanges define a portion of an upper surface of the data gathering system and a scale supported by the flanges defines the remaining upper surface which comprises a weighing platter for the scale. A scale calibrating and zeroing system is incorporated into the support flanges to be accessible through the upper surface of the data gathering system such that the scale can be periodically zeroed and calibrated as necessary to maintain the accuracy of the scale without removal of the data gathering system from the counter.
Abstract: A weighing in motion (WIM) apparatus and method in which scale platforms are provided exhibiting a high rigidity selected to achieve a relatively high natural frequency response characteristic. These platforms are combined with instrumentation wherein load cell derived signal outputs are digitized at a conversion or sampling rate effective to permit an identification of amplitude data correlative to vehicle weight. In particular, the sampling rate is selected so as to isolate and detect peak amplitude output of the system which is directly correlatable to truck weight. The invention derives from a recognition that, during the dynamics of movement of a vehicle such as a truck over the rigid scale platform structures, there occurs a decoupling of the mass of the truck from the scale permitting its response to the weight of the truck without significant loss of natural frequency bandwidth.
Abstract: Apparatus for weighing vehicles in motion includes a base to be anchored to a roadbed below ground level in the path of moving vehicles and a pair of scale platforms mounted on the base for receiving the wheels on the opposite sides of the moving vehicles. Load cells are provided between the base and the platform for producing signals indicating the load applied by each wheel on the platform. A pair of flexure struts is connected between each platform and the base to apply a preload and permit relative movement therebetween in the vertical direction and to resist relative movement in the horizontal direction. The flexure struts extend lengthwise in the direction of traffic flow and are resistant to loads in that direction while being flexible in the vertical direction to permit application of the preload and flexing of the load cells. The dynamic weight signals from the load cells are converted to digital form and operated on to provide information as to the weights of the passing vehicles.
Abstract: A dual beam moment-insensitive load cell is hermetically sealed in a bellows or partial-bellows enclosure. The enclosure may have convolutions over substantially its entire length which permits it to flex easily in the direction of load cell bending. The enclosure is made resistant to elastic buckling under torsional forces produced by off-center loading of the load cell by one or more rods spaced circumferentially about the enclosure and connecting together a number of the convolutions after the convolutions are aligned. The alignment and torsional stiffening resist elastic buckling of the enclosure and resulting error in the output of the load cell. Another form of enclosure has one or more convolutions at each end and joined by a relatively straight, non-convoluted wall which itself is resistant to torsional elastic buckling. The resistance of the wall to torsional elastic buckling can be increased by increasing its thickness uniformly or by applying stiffener rods thereto.
Abstract: Load cells incorporating rocker pin configured columnar central structures within a weighing system have the attribute of self-erecting upon being displaced from a vertical orientation due to dynamic transverse loading effects, as may be occasioned by vehicle movements onto a scale. The resultant transient vector forces thus developed have been observed to cause a rotational phenomenon in the rocker pin configured cells which causes unacceptable damage to the instrumentation control communication components of the load cell system. A mounting technique for such load cells is developed wherein only these rotation inducing forces are restrained, while the vertical force vectors representing valid load data are maintained in an unrestricted or uncompromised manner. In one aspect of the invention, a hexagonal form of mounting between a rocker pin neck-contact surface region and a corresponding receiver cavity achieves a fully pivoting and freely abutting geometry while effecting the noted restriction of rotation.
September 26, 1989
Date of Patent:
September 11, 1990
Toledo Scale Corporation
Nigel G. Mills, Larry C. Heckendorn, Curtis W. Long, Richard T. Smigel
Abstract: A load cell stamped from a single plate includes a pair of strain gauges mounted on each lateral edge of the plate and a slot extending between laterally opposite strain gauges. The load cell so formed can be widened to provide increased torsional stiffness and resistance to off-center loading while providing good load cell performance in all other respects. In a low profile scale including the load cell, one longitudinal end of the load cell is connected to a load receiving element and the other fixed to a base plate and ground.
Abstract: A digital load cell includes a rocker pin, guided beam, torsion ring or other counterforce, a circuit board mounted on the counterforce and an enclosure sealing the circuit board and all but the load bearing surfaces of the counterforce. The circuit board includes an A/D converter and a microcomputer. Digital communication is provided with the circuit board through a connector mounted on the enclosure. Weight data are corrected digitally. The load cell may be calibrated, characterized, controlled and monitored without physically penetrating the enclosure. One or a number of digital load cells may be connected to a computer or controller to form one or more weighing scales.
November 30, 1987
Date of Patent:
March 28, 1989
Toledo Scale Corporation
Benny N. Dillon, Neil C. Griffen, Mark E. Weihs
Abstract: Multiple digital load cells forming one or more weighing scales are connected together and to a common master controller in a local area network. The digital load cells are polled by and provide weight readings to the master controller. The weight readings are combined with a load position correction factor for each load cell and summed to provide a weight indication corrected for load position. The values of the load position correction factors are determined during set up of the scale and stored at the master controller. An individual load cell can be diagnosed remotely and replaced if defective. A new load position correction factor is determined and stored for a replacement load cell.
Abstract: A digital weighing scale is compensated for the effects of off-center loading by determining the position of the load and calculating a corrected weight value according to such position. Position sensing transducers are mounted on the load cell to provide information regarding the position of the load on the weighing scale. An expression for corrected weight as a function of load position and magnitude is determined for the particular scale and stored. The expression is used to calculate corrected weight according to the magnitude and position of each weight placed on the scale. The load cell may include a counterforce of substantially any type including single bending beam, dual bending beam or capacitive structure, and the load magnitude and position sensors may be of substantially any type including strain gages and capacitive sensors.